Large Colon and Rectum Flashcards by Cameron MacFarlane

Describe the anatomical difference between Crohn’s and Ulcerative Colitis.

Crohn’s is mouth to anus.

UC is colon and rectum only.

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Describe the pathological difference between Crohn’s and UC.

Crohn’s -> granulomas and skip lesions (+ deep ulceration, cobblestoning, cryptitis, pseudopolyps)
UC -> Superficial irregular crypts. Basal lymphoplasmocytic infiltrate

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Name the genetic causes of Crohn’s and UC.

Crohn’s -> chromosome 16 -> HLA-DR1, HLA-DQw5

UC -> NOD-2, HLA-DR2

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What are the presenting complaints of Crohn’s and UC?

Crohn’s -> abdo pain, perianal disease, diarrhoea

UC -> abdo pain, diarrhoea/blood, pus/mucus

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Describe the lymphocytes involved in Crohn’s and UC.

Crohn’s -> TH1

UC -> TH1/TH2/NKTC

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Describe the role of smoking and NSAIDs in Crohn’s and UC/

Crohn’s -> both bad

UC -> smoking is good, NSAIDs bad

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Which investigations should be used in Crohn’s?

Ba follow through, MRI, technectium WBC scan

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Which investigations should be used in UC?

CRP/albumin, AXR, endoscopy, histology

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Describe the Truelove/Witt criteria for UC.

> 6 bloody stools in 24 hours, + fever, tachycardia, anaemia, increased ESR

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Name and describe the drug treatments for Crohn’s and UC.

Steroids (short course 6-8 wks)
Immunosuppressants (maintenance C/steroid-saving UC)
Anti-TNF therapy
5ASA therapy (UC)
Biosimilars

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Describe IBS.

Irritable bowel syndrome - a functional GI disorder.

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What are the Rome III criteria used to diagnose IBS?

Recurrent abdo pain/discomfort + 2 of
- improvement with defecation
- change of frequency of stool
- change of appearance of stool
For 3 days/month for 3 months

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What are the six Manning criteria for IBS?

pain relief on defecation
more frequent stools
visible abdo distension
passage of mucus
looser stools
sense of incomplete evacuation

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What are the red flag symptoms for IBS?

Weight loss, blood in stool, anaemia, fever, history of progressive pain

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Which are the risks for IBS?

<45, female, family history, mental health problems

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What are the three types of IBS?

IBS-C (constipation), IBS-D (diarrhoea), IBS-M (mixed)

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What should be used to treat IBS-C?

Diet (more fruit and veg)
Short term antispasmodics
Fibre
Osmotic laxatives
5-HT4 antagonists

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What should be used to treat IBS-D?

Diet (avoid fruit/veg - FODMAP diet)
Short term antispasmodics
Loperamide (reducing frequency)
Codeine phosphate (pain)
5-HT3 antagonists
Antidepressants/anticonvulsants

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What is intestinal failure?

Inability to maintain nutrition/fluid status from obstruction, dysmotility, resection, congenital defect, or disease

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Describe the three types of intestinal failure.

Type 1 - acute, self-limiting, 2 weeks
Type 2 - acute, post surgery, 4 weeks
Type 3 - chronic, short bowel syndrome

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How should the three types of intestinal failure be treated?

1 - fluid, electrolytes, PPIs
2 - parenteral +/- enteral
3 - home parenteral nutrition

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Define short bowel syndrome.

A short bowel < 200 cm (normally 250-1050)

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What are the last resorts for short bowel syndrome?

Transplant, bowel lengthening.

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Name the three types of home parenteral nutrition (HPN).

Peripherally inserted central catheter (PICC), central venous, and portacath

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What are the complications of home parenteral nutrition?

Pneumothorax, arterial puncture, sepsis, thrombosis

Name the four types of malignant tumours in the large colon.

Polypoid adenocarcinoma, carcinoid, sarcoma, lymphatomous

What is the macroscopic view of polyps and tumours?

Pedunculated, sessile, flat, irregular surface/stalk

What are the majority of benign polyps in the colon?

Adenomas

Which genetic factors convert adenomas to carcinomas, then to metastasis?

17p/18q and p53 | nm23 (mets)

Name the three main types of adenoma.

Tubular, villous, tubulovillous

Name the three Duke's polyp categories.

A -> confined -> 90% prognosis B -> through propria -> 70% C -> lymph nodes -> 35%

Where are the majority (75%) of colon tumours located? Describe the presentation of both locations.

75% - descending and sigmoid -> blood PR, altered bowel habit, obstruction 25% - ascending -> anaemia, weight loss

Describe the two types of multiple polyp conditions in the large bowel.

Hereditary non-polyposis coli (HNPC, <100 polyps) Familial adenomatous polyposis (FAP, >100 polyps) HNPC is late; DNA mismatch repair FAP is early; tumour suppression

What is diverticular disease?

Mucosal herniation through muscle coating

What is diverticulitis?

Inflammation of diverticulosis (which is diverticula). May also bleed.

How is diverticular disease found?

Usually incidental. Ba enema or sigmoidoscopy

What is the main presentation of diverticulitis? What are the complications?

LIF pain, sepsis, altered bowel habit | Abscess, perforation, haemorrhage, fistula, stricture

How should 1. uncomplicated, 2. complex, and 3. abscess diverticulitis be treated?

1. oral abx, 2. Hertmann's, 3. Drain/lavage

What is angiodysplasia?

A small vascular malformation of the gut, forming submucosal lakes of blood

What are the six main causes of bowel obstruction?

Cancer, stricture, volvulus, pseudo-obstruction, constipation, infarcation

How should bowel obstruction be treated?

Resus, operation, stenting

Give some ways STIs can be transferred to the GI tract.

Passive transfer of vaginal secretion, rimming, sex toys/fingers, systemic/local spread

Give some risk factors that make STI more likely.

< 25, change in partners, no condom, MSM, past history, deprivation, black ethnicity

How does Shigela spread as an STI? Who is at risk?

Faecal -> oral route. Bisexual/gay men

How do gonorrhoea and chlamydia spread? How do they both present?

Infected fluids in contact with mucous membranes G: abdo pain, diarrhoea, rectal bleeding/discharge, tenesmus. Purulent exudate C: similar, less severe. Anal discomfort/itch/discharge

What are the risk factors for LGV? How does it present?

Group sex, MSM, drug use, syphilis, hep C | Ulcers, inguinal/ano-rectal syndromes, fistulae

What is the differential diagnosis of 'piles'?

Haemorrhoids, herpes, syphilis, LGV, anal cancer

How does syphilis present?

Primary: as a single solitary painless ulcer Secondary: patches, ulcers, inflammation, hepatitis, procto-colitis

How can HPV lead to anal cancer?

Anal intraepithelial neoplasia: AIN

What are the general and dietary factors that may predispose to colorectal cancer?

Older age, obesity, smoking | High fat/sugar/alcohol/meat intake, low fibre

Describe the genetic aetiology of colorectal cancer.

75-95% have no genetic factors. | Genetic factors: APC (100% will get cancer), p53, UC and Crohn's (but UC > Crohn's).

Describe the four ways in which colorectal cancer can spread.

Direct, lymphatic, blood borne (liver/lung), or transcoelomic (rare)

Describe the three main ways in which colorectal cancer is picked up on.

``` Bowel screening (age 50-72) Urgent referral (red flag symptoms) - gastroenterologist decides whether SOPD/endoscopy Emergency (obstruction, perforation, bleeding etc) ```

Where do most colorectal cancers present - the left or right colon?

75% left, 25% right

Describe the difference between colorectal cancer that presents in the left vs right colon.

Left - rectal bleeds, incomplete evacuation, constipation | Right - Anaemia, tiredness, change in bowel habit, weight loss, colicky abdo pain, mass in abdomen

Which investigations are (primarily) used for colorectal cancer?

Sigmoidoscopy/colonoscopy (depending on tumour location) and CT colonography (Barium enemas are now widely disregarded)

Describe the three main mass findings on endoscope.

Sessile (flat) or pedunculated (mushroom) polyp, or cancer

What is required to prepare a patient for a CT colonography?

Bowel perforation, faecal tagging, CO2 insuppuration, buscopan IV

Describe what a CT scan would show in the presence of colorectal cancer.

An irregular, narrow lumen, speculated outer border, sharp demarcation

Which tools are used to stage 1. colonic cancer and 2. rectal cancer?

1. CT, 2. MRI

What are the three main types of surgery for colorectal cancer?

Open, laparascopic, robotic

Why is laparascopic surgery generally preferred to open surgery?

Leaves fewer scars/wounds, same results

Which things are done in colorectal paliation?

Stenting, radio/chemo therapy, defunctioning, bypass

What is rectal prolapse?

Prolapse of the anterior mucosa (partial) or full

How may patients describe an anal fissure?

Like passing glass

Large Colon and Rectum Flashcards

(65 cards)